System for accurately weighing solids and control mechanism for same

ABSTRACT

A system, including a closed chamber ( 20 ) having a gas inlet ( 22 ) and a gas outlet ( 24 ) is shown and described. An inert gas supply under positive pressure is connected to the gas inlet, and a bubbler is connected to the gas outlet. The bubbler includes a compartment that is partially filled with liquid so as to define a head space, an inlet operatively connected to the gas outlet, a vent, and a vacuum line in fluid communication with the head space so that the head space has a negative pressure.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is the National Stage of International Application No.PCT/US2006/011519, filed Mar. 27, 2006, which claims the benefit of U.S.Provisional Application Nos. 60/670,370, filed Apr. 12, 2005, thedisclosure of which is incorporated herein by reference in its entirety.

FIELD OF THE INVENTION

The present invention relates to apparatuses, systems and processes forweighing or otherwise evaluating a mass of material. Certain aspects ofthe invention may include accepting, weighing and dispensing batches ofmaterial. Certain other aspects of the invention may include pressureregulators for the apparatuses, systems and processes of the presentinvention.

BACKGROUND OF THE INVENTION

Methods of manufacturing goods from a variety of ingredients typicallyinclude a step of measuring the individual ingredients prior tocombining them. Accuracy of the measurements can be extremely importantin some applications, to the point where uncontrolled variation canaffect the operability or desired properties of the final manufacturedgood.

One of the suitable uses for the present invention is weighing, andoptionally dispensing, batches of monomer and additives that can becombined to form polymers from which fibers are ultimately made. Forexample, azole-forming monomers (or monomer complexes) and metaladditives can be processed by the apparatuses and systems of the presentuntil a mass of material with a known weight is obtained. The mass ofmaterial is then reacted in a solution comprising polyphosphoric acid toform a polyareneazole polymer. The polymer is then extruded through aspinneret to form individual fibers. The fibers can be further processedinto yarns, fabrics, and other articles. Accurately weighing the monomerand additives in this example is important for obtaining a fiber havinga desired fiber strength, among other properties.

It should be noted that the present invention is not limited to theexemplary use identified above. The apparatuses and systems are suitablefor a variety of solids handling applications, including, as furtherexamples, baking ingredients, gun powder, and pharmaceutical formulationingredients.

SUMMARY OF THE INVENTION

In accordance with one preferred embodiment of the present invention,there has now been provided an apparatus for regulating pressure in aclosed system, comprising a compartment partially filled with a liquidso as to define a head space above the liquid; a vacuum port in fluidcommunication with the head space, so that an environmental pressure ofthe head space is negative; a vent line for regulating pressure in thehead space, the vent line adjustably extending into the liquid; aprocess line including a first end connected to the closed system, andan opposing second end adjustably extending into the liquid.

In accordance with another preferred embodiment of the presentinvention, there has now been provided a system, comprising a closedchamber including a gas inlet and a gas outlet; an inert gas supplyunder positive pressure connected to the gas inlet; and a bubblerconnected to the gas outlet, the bubbler including a compartment that ispartially filled with liquid so as to define a head space, an inletoperatively connected to the gas outlet, a vent, and a vacuum line influid communication with the head space so that the head space has anegative pressure.

In accordance with yet another preferred embodiment of the presentinvention, there has now been provided a process for regulating thepressure in a closed system by use of a regulating device, the devicecomprising a compartment partially filled with a liquid so as to definea head space above the liquid; a vacuum supply line in fluidcommunication with the head space; a vent line including an end thatadjustably extends into the liquid for regulating pressure within thehead space; and a process line including a first end connected to theclosed system and an opposing second end adjustably extending into theliquid; and the process comprising the steps of applying a vacuum to thehead space via the vacuum supply line; establishing a pressureestablishing a pressure in the closed system by adjusting position ofthe process line second end disposed in the liquid; wherein the level ofvacuum applied to the head space is sufficient to cause bubbles to format the vent line end disposed in the liquid.

These and various other features of novelty, and their respectiveadvantages, are pointed out with particularity in the claims annexedhereto and forming a part hereof. However, for a better understanding ofaspects of the invention, reference should be made to the drawings whichform a further part hereof, and to the accompanying descriptive matter,in which there is illustrated preferred embodiments.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of one preferred apparatus embodiment ofthe present invention that is useful for weighing and dispensing a massof material;

FIG. 2 is a perspective view of another preferred apparatus embodimentin accordance with the present invention, showing a portion for mixingup to three different raw materials after batches of the same have beenmeasured;

FIG. 3A is an exploded perspective view of one preferred valve and valveactuator provided by the present invention;

FIG. 3B is an assembled perspective view of the valve and valve actuatorshown in FIG. 3A;

FIG. 4 is cross-sectional view of one preferred pressure regulator inaccordance with the present invention; and

FIG. 5 is a series of three cross-sectional views of the pressureregulator shown in FIG. 4, with associated dip tubes at differentpositions within a partially liquid filled central compartment.

DETAILED DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS

The present invention may be understood more readily by reference to thefollowing detailed description of illustrative and preferred embodimentstaken in connection with the accompanying figures that form a part ofthis disclosure. It is to be understood that the scope of the claims isnot limited to the specific devices, methods, conditions or parametersdescribed and/or shown herein, and that the terminology used herein isfor the purpose of describing particular embodiments by way of exampleonly and is not intended to be limiting of the claimed invention. Also,as used in the specification including the appended claims, the singularforms “a,” “an,” and “the” include the plural, and reference to aparticular numerical value includes at is expressed, another embodimentincludes from the one particular value and/or to the other particularvalue. Similarly, when values are expressed as approximations, by use ofthe antecedent “about,” it will be understood that the particular valueforms another embodiment. All ranges are inclusive and combinable.

Referring now to the figures, wherein like features are labeled withlike reference characters, an exemplary apparatus 10 in accordance withthe present invention is shown in FIG. 1, including a chamber 20, threeindividual scales 30, three receptacles 40 operatively connected toscales 30, and three dispensing conduits 50. Although FIG. 1 showsmultiple scales, receptacles and dispensing conduits, alternateembodiments contain fewer and greater numbers of these components.

In one preferred embodiment, chamber 20 is an isolation chamber havingenvironmental conditions that are different than those surroundingchamber 20. For example, the chamber can be discontinuously orcontinuously purged with an inert gas (e.g., nitrogen or argon), so asto render the chamber substantially moisture and/or oxygen free to helpprevent material contamination. As shown, chamber 20 has a gas inlet 22for introducing an inert gas and a gas outlet 24 for exhausting theinert gas. Chamber 20 may also have controlled pressure and/ortemperature levels. Thus, components extending into chamber 20preferably have sealed entry ways. Chamber 20 can be constructed fromany number of materials, such as, for example, stainless steel, acrylicplastic, glass, polycarbonate, or a combination of different materials.As shown in FIG. 1, chamber 20 is constructed to include a frame 26 anda plurality of panels 28. By way of example, frame 26 may be made out ofstainless steel and the panels 28 out of a transparent polymericmaterial, such as an acrylic.

Each of scales 30 is preferably a high precision scale capable ofyielding, for example, a weight measurement accuracy to 0.1 grams for a20kilogram mass. One suitable scale is model number SG32001 availablefrom Mettler Toledo corporation of Columbus, Ohio. It is noted thatother scales can also be used in accordance with the present invention,and that the appended claims are not limited in scope to scalespossessing a certain measurement precision unless the same is explicitlyrecited. “Scale,” as that term is used herein, includes all devicesencompassed by lay person and technical dictionaries, and furtherincludes, but is not limited to, devices including a load cell.

Receptacles 40 are shown suspended from scales 30, but other connectiveand positional arrangements can equally be employed. Receptacles 40 canhave various geometries, including the conical shape as shown in FIG. 1.Conical and other similar shapes help to receptacle. Each of receptacles40 includes an inlet 42 and an outlet 44. The outlets 44 are covered byan exemplary valve 60, which is discussed in more detail below. In apreferred embodiment, inlet 42 is spaced apart from, or at leastphysically unconnected from, a material supply line 29, and outlet 44 isspaced apart from, or at least physically unconnected, from dispensingconduit 50. Connecting a component to receptacle 40, other than thescale, is believed to reduce weight measurement accuracy, and thereforeconnections are avoided in applications where accuracy is critical. Thispreferred configuration should not be interpreted as a disclaimer forunderstanding the breadth of the invention and claim constructionpurposes, as claims that do not specifically recite such a configurationare not so limited.

Along these same lines, an actuator 62 for operating valve 60 ispreferably capable of being decoupled from valve 60 while weighing abatch of material. As shown in FIG. 1, actuator 62 preferably extendsthrough and is held by one of chamber panels 28. For example, anactuator axis can pass through an o-ring lined aperture in the chamberpanel.

A more detailed view of exemplary valve 60, actuator 62, and relatedcomponents is illustrated in FIGS. 3A and 3B. Actuator 62 includes ahandle 63, an axis 64, and a male coupling 65 having opposingprojections 66. Valve 60 includes a valve body 68, a connection member69, and a female coupling 70. Female coupling 70 is attached to a shaft71, via hardware 74, which is attached to a disk-shaped member 72rotatably disposed within valve body 68. Disk-shaped member 72 is shownin a partially open position for illustration purposes only (obviously,handle 63, male coupling 65 and female coupling 70 would be rotated to asecond position that is not shown to cause the rotation of thedisk-shaped member 72). When material is being fed into receptacles 40,or when a weight measurement is being taken, projections 66 do notcontact female coupling 70; that is, actuator 62 is decoupled from valve60. To discharge a batch of material, handle 63 is rotated, causingprojections 66 to rotate and engage channels 73 defined on femalecoupling 70. Additional handle rotation will cause the disk-shapedmember 72 to rotate sufficiently to allow the batch of materialaccumulated in receptacles 40 to be discharged. One suitable valve is abutterfly valve offered by Asahi. Other valve and actuator designs canequally be used in accordance with the present invention. Furthermore,in alternate embodiments, the valve actuator is completely disposedwithin the chamber rather than extending through a panel of the chamber.With this arrangement and with reference to FIG. 2 showing anotherexemplary apparatus 11, a sealed glove 78 extending into the chamber canbe employed to manually operate the actuator. Automated actuators canalso be employed—extending into the chamber or completely disposedwithin the chamber. be used for fine weight adjustments to a batch ofmaterial accumulating in receptacles 40. Each of dribblers 80 includes acup 82, and an actuator 84 having a handle 85 that extends to theoutside of chamber 20 through one of the chamber panels 28. The dribbleron the left is illustrated in a complete open configuration, wherebymaterial is fed directly into receptacle 40 from material supply line29. The dribbler in the middle is illustrated in a complete closedconfiguration, whereby material can be fed into the cup and notreceptacle 40. The closed configuration can also be used when making aweight measurement to prevent additional material from accidentallybeing fed into receptacles 40. The dribbler on the right is shown beingused to add incremental amounts of material to receptacle 40 for fineweight adjustments. Similar to the valve actuator, dribbler actuator 84could alternatively be disposed inside of chamber 20, and be operatedremotely or via a sealed glove arrangement. In preferred embodiments,dribblers 80 do not contact receptacles 40.

As noted above, in one preferred embodiment chamber 20 has a controlledenvironment. An inert gas (e.g., nitrogen or argon) can be pumped intochamber 20 via gas inlet 22 to render the chamber substantially moistureand/or oxygen free. The inert gas may be supplied either continuously ordiscontinuously. The inert gas exits chamber 20 through an exhaust port24. An apparatus for regulating pressure is preferably connected toexhaust port 24 to prevent oxygen from entering the chamber via theexhaust port.

One embodiment of this invention is an apparatus for regulating pressurein a closed system, comprising a compartment partially filled with aliquid so as to define a head space above the liquid; a vacuum port influid communication with the head space, so that an environmentalpressure of the head space is negative; a vent line for regulatingpressure in the head space, the vent line adjustably extending into theliquid; a process line including a first end connected to the closedsystem, and an opposing second end adjustably extending into the liquid.A system, as referred to herein, includes, in addition to the chamber,the associated conduits that comprise any inlets or outlets to thechamber, plus any component connected to the chamber that is exposed tothe internal environment in the chamber. A system is a closed system ifit has one or more methods of control of the atmospheric environment inthe system such that it is maintained in a state different than ambientconditions, such as, for example, under an inert gas or a pressurehigher or lower than atmospheric pressure. A system can also be a closedsystem if it has one or more methods of control of a first atmosphericenvironment in the system in a state substantially different from thatof a second environment in process equipment or piping in fluid orotherwise communication with that system. In particular, and in somepreferred embodiments pressure. Other properties of the closed systemenvironment can also be controlled as desired, such as moisture contentor temperature. Such a closed system may have material pass through thesystem, with the methods of control maintaining the desiredenvironmental conditions.

Referring now to FIGS. 4 and 5, an exemplary apparatus for regulatingpressure, which can also be referred to as a bubbler, is depicted. Asshown in the figures, bubbler 100 is a vacuum powered pressureregulator, that when operatively connected to a closed chamber, such aschamber 20, is capable of controlling the pressure level within a closedchamber. Bubbler 100 is essentially a container having three sealedcompartments: a central compartment 110 partially filled with a liquid111 (preferably an oil), and two side compartments 112 and 114. The twoside compartments are optional, and primarily serve as liquid trapzones. The bubbler is connected to a chamber via process line 115, withone end of process line 115 configured for attachment to a chamber port(e.g., exhaust port or gas outlet 24 that is shown in FIG. 1) and theopposing end configured for attachment to bubbler 100—here, attachmentto a barbed nipple extending from side compartment 112. In alternativeembodiments, process line 115 could be attached directly to centralcompartment 110.

As shown in FIGS. 4 and 5, process line 115 is fluidly connected tocentral compartment 110 via a flexible line 116 and a first dip tube 117(preferably sealed with an o-ring) that is adjustably disposed in liquid111. Bubbler 100 includes a vent line 120 that is connected to optionalside compartment 114, is fluidly connected to central compartment 110via a flexible line 121, and that terminates with a second dip tube 122(also preferably sealed with an o-ring). Second tip tube 122 is alsoadjustably disposed in liquid 111. Central compartment 110 includes ahead space 130 defined above liquid 111, and a vacuum port 132 in theform of a barbed nipple that is in fluid communication with head space130. A vacuum supply line 134 is connected to vacuum port 132.

Exemplary bubbler 100 is configured to maintain a stable level ofpressure within a closed chamber. Pressure fluctuations are undesirablein applications where accurate weight measurements are required sincethe fluctuations can affect precision of the scales. In preferredembodiments, a pressure level in a closed chamber is controlled towithin about 0.5 inch of water head (0.125 kPa), preferably within about0.25 inch of water head (0.062 kPa), and more preferably within about0.125 inch water head (0.031 kPa).

With reference to FIGS. 1 and 4, inert gas is supplied to chamber 20 viagas inlet 22 and exhausted via gas outlet 24. Bubbler 100 is connectedto gas outlet 24 by process line 115. A vacuum is applied to head space130 at a sufficient level to cause bubbles to form at position of seconddip tube 122, and pressure inside closed chamber 20 is controlled byadjusting the position of first dip tube 117. For example, and withreference to FIG. 5, configuration 1 will result in a negative pressurefor process line, configuration 2 will control the process line atatmospheric pressure, and configuration 3 will all positive pressure forthe inert gas sweep.

It is to be understood that the bubbler configuration shown anddescribed above is a preferred embodiment, and that the scope of theappended claims is not limited to the same. Numerous variations tobubbler 100 are within the scope and spirit of the invention herein.

One preferred embodiment of this invention is a system comprising aclosed chamber including a gas inlet and a gas outlet; and inert gassupply under positive pressure connected to the gas inlet; and a bubblerconnected to the gas outlet, the bubbler including a compartment that ispartially filled with liquid so as to define a head space, an outletoperatively connected to the gas outlet, a vent, and a vacuum line influid communication with the head space so that the head space has anegative pressure.

In a preferred embodiment, a chamber is isolated or closed if it has oneor more methods of control of the atmospheric environment in the chambersuch that the chamber is maintained in a state different than ambientconditions, such as, for example, under an inert gas or a pressurehigher or lower than atmospheric pressure. A chamber can also be closedif it has one or more methods of control of a first atmosphericenvironment in process equipment or piping in fluid or otherwisecommunication with that chamber.

Another embodiment of this invention is a process for regulating thepressure in a closed system by use of a regulating device; the devicecomprising a compartment partially filled with a liquid so as to definea head space above the liquid, a vacuum supply line in fluidcommunication with the head space, a vent line including an end thatadjustably extends into the liquid for regulating pressure within thehead space, and a process line including a first end connected to theclosed system and an opposing second end adjustably extending into theliquid; the process comprising the steps of (a) applying a vacuum to thehead space via the vacuum supply line; (b) establishing a pressure inthe head space by adjusting position of the vent line end disposed inthe liquid, and (c) establishing a pressure in the closed system byadjusting position of the process line second end disposed in theliquid; wherein the level of vacuum applied to the head space issufficient to cause bubbles to form at the vent line end disposed in theliquid. In some embodiments, the closed system is swept with an inertgas that exits the closed system via the process less. In otherembodiments, the process controls the pressure level within the closedsystem to within about 0.5 inch of water head (0.125 kPa), preferablywithin head (0.031 kPa).

The apparatuses, systems and processes of at least some of the preferredembodiments are particularly useful for weighing and dispensingparticulate materials for making fiber polymers. An exemplary fiberpolymer is a polyareneazole polymer, which is made by reacting a mix ofdry ingredients with a polyphosphoric acid (PPA) solution. The dryingredients may comprise azole-forming monomers and metal powders.Accurately weighed batches of these dry ingredients can be obtainedthrough employment of at least some of the preferred embodiments of thepresent invention.

Exemplary azole-forming monomers include 2,5-dimercapto-p-phenylenediamine, terephthalic acid, bis-(4-benzoic acid), oxy-bis-(4-benzoicacid), 2,5-dihydroxyterephthalic acid, isophthalic acid,2,5-pyridodicarboxylic acid, 2,6-napthalenedicarboxylic acid,2,6-quinolinedicarboxylic acid, 2,6-bis(4-carboxyphenyl)pyridobisimidazole, 2,3,5,6-tetraaiinopyiidine, 4,6-diaminoresorcinol,2,5-diaminohydroquinone, 1,4-diamino-2,5-dithiobenzene, or anycombination thereof. Preferably, the azole forming monomers include2,3,5,6-tetraaminopyridine and 2,5-dihydroxyterephthalic acid. Incertain embodiments, it is preferred that that the azole-formingmonomers are phosphorylated. Preferably, phosphorylated azole-formingmonomers are polymerized in the presence of polyphosphoric acid and ametal catalyst.

Metal powders can be employed to help build the molecular weight of thefinal polymer. The metal powders typically include iron powder, tinpowder, vanadium powder, chromium powder, and any combination thereof.

The azole-forming monomers and metal powders are mixed and then themixture is reacted with polyphosphoric acid to form a polyareneazolepolymer solution. Additional polyphosphoric acid can be added to thepolymer solution if desired. The polymer solution is typically extrudedor spun through a die or spinneret to prepare or spin the filament.

Aspects of the present invention have been described with reference toprocessing particulate material associated with fiber polymers. Thepresent invention is not limited to this application, and can be usedfor any number of solids and non-solids processing.

While the present invention has been described in connection with thepreferred embodiments of the various figures, it is to be understoodthat other similar embodiments may be used or modifications andadditions may be made to the described embodiment for performing thesame function of the present invention without deviating therefrom.Therefore, the present scope in accordance with the recitation of theappended claims.

1. An apparatus for regulating pressure in a closed system, comprising:a) a compartment partially filled with a liquid so as to define a headspace above the liquid; b) a vacuum port in fluid communication with thehead space, so that an environmental pressure of the head space isnegative; c) a vent line for regulating pressure in the head space, thevent line adjustably extending into the liquid; d) a process lineincluding a first end connected to the closed system, and an opposingsecond end adjustably extending into the liquid.
 2. The apparatus ofclaim 1, wherein the apparatus is capable of controlling a pressurelevel within the closed system to within about 0.125 kPa.
 3. Theapparatus of claim 1, wherein the apparatus is capable of controlling apressure level within the closed system to within about 0.062 kPa. 4.The apparatus of claim 1, wherein the apparatus is capable ofcontrolling a pressure level within the closed system to within about0.031 kPa.
 5. A closed system, comprising: a) a closed chamber includinga gas inlet and a gas outlet; b) an inert gas supply under positivepressure connected to the gas inlet; and c) an apparatus according toclaim 1, wherein the process line first end is connected to the gasoutlet.
 6. A system, comprising: b) an inert gas supply under positivepressure connected to a gas inlet; and c) a bubbler connected to a gasoutlet, the bubbler including a compartment that is partially filledwith liquid so as to define a head space, an inlet operatively connectedto the gas outlet, a vent, and a vacuum line in fluid communication withthe head space so that the head space has a negative pressure.
 7. Thesystem of claim 6, wherein a first dip tube adjustably extends from theinlet to the liquid and into the liquid, and a second dip tubeadjustably extends from the vent to the liquid and into the liquid. 8.The system of claim 6, wherein the bubbler further includes a liquidtrap zone disposed between the inlet and the compartment.
 9. The systemof claim 6, wherein the bubbler is capable of controlling a pressurelevel within the closed chamber to within about 0.125 kPa.
 10. Thesystem of claim 6, wherein the bubbler is capable of controlling apressure level within the closed chamber to within about 0.062 kPa. 11.The system of claim 6, wherein the bubbler is capable of controlling apressure level within the closed chamber to within about 0.031 kPa. 12.A process for regulating the pressure in a closed system by use of aregulating device, the device comprising: i) a compartment partiallyfilled with a liquid so as to define a head space above the liquid; ii)a vacuum supply line in fluid communication with the head space; iii) avent line including an end that adjustably extends into the liquid forregulating pressure within the head space; and second end adjustablyextending into the liquid; the process comprising the steps of: a)applying a vacuum to the head space via the vacuum supply line; b)establishing a pressure in the head space by adjusting position of thevent line end disposed in the liquid; and c) establishing a pressure inthe closed system by adjusting position of the process line second enddisposed in the liquid; wherein the level of vacuum applied to the headspace is sufficient to cause bubbles to form at the vent line enddisposed in the liquid.
 13. The process of claim 12, wherein the closedsystem is swept with an inert gas that exits the closed system via theprocess line.
 14. The process of claim 12, wherein the pressure withinthe closed system is controlled to within about 0.125 kPa.
 15. Theprocess of claim 12, wherein the pressure within the closed system iscontrolled to within about 0.062 kPa.
 16. The process of claim 12,wherein the pressure within the closed system is controlled to withinabout 0.031 kPa.